I can’t do a Sit Up

I have a confession.  I can’t do a sit up.  I mean, I can do a sit up.  But, it is either reeeaallllyyyy slow, or involves some pretty aggressive arm flailing.  You know, like way up over you head and then….wooosh…throw your arms forward until you are upright…??

I can usually hide my lack of sit up ability, but I was totally exposed in a Core class that I took the other day.  The goal of the exercise that I utterly failed at was to lie with your feet on the ground, knees bent, and crunch up until your shoulders and upper ribs were off the floor.  I got my shoulders up, and then was 100% stuck.  Despite the ridiculous amount of effort my poor abs were putting in, my torso was not curling up any further.

Not. Having. It.

You know what I blame (besides my utter lack of commitment to actually practicing situps)?  Crunches.


I grew up in the generation of “core training” and “don’t do sit ups, they’ll hurt your back”.  Well, guess what?  The era of curling only your upper body up off the floor did more damage than good (despite all of the beautiful pictures out there of men and women with six-packs in a semi-crunch pose…). I did crunches for pretty much all of my adolescence through my 20’s.  Now I have a strong abs and my back hurts and I can’t do a sit up.  (Be honest.  Can you?  Without help of any kind?  Knees bent…just sit up.  Try it.)

If you can, well done.  You’re amazing. (Seriously)  And one of very few.  If you can’t, you’re probably like me.  A victim of the crunch.

Why has the crunch (i.e. “core training”) led to such a huge problem?  Because it wasn’t training the right muscles.  Well, at least it wasn’t training all of them.  Of course your abdominal muscles are important to be able to do a sit up, but you know what’s more important?  Your iliospoas – a.k.a your hip flexors.


(There are others, of course…your hips are complex…but we’re going to stick with the biggie for now).

Your iliospoas, or hip flexor, is a pairing of two muscles – the iliacus and the psoas.  They connect your low back (T12-L5) to the front of your femur bone.  When the iliospoas contracts, your leg goes up, or flexes.  If you don’t actively use them, they get tight and weak.  It’s actually pretty easy to let this happen, because your quads also flex your thigh.  So, if you have strong leg muscles, you can compensate for weak hip flexors.  This is what happened to me.

How can you tell if you have weak hip flexors?  Two pretty obvious ways.  1) If, when you are standing upright, your butt sticks out behind you and your low back arches, you most likely have weak/tight hip flexors.  2) If you are pretty active but still have low back pain (although the hamstrings are often blamed) you more likely have weak/tight hip flexors.

anterior pelvic tilt

You could also try a test.  Stand up as straight as you can and pull one knee up into your chest.  Let it go, and see if you can hold it up without leaning backward or letting your knee come down  (you may want to do this in a mirror or get someone to watch you).  If you have to lean back or your leg comes down a lot, you definitely have weak/tight hip flexors.

So, what do you do?

There are several exercises you can use to strengthen this muscle.

1) Lay on your back, one leg bent and one straight.  Raise your straight leg to 90 degrees and then lower, slowly.

2) Stand up straight and bring your knee up to your chest (like you did in the above test).  Let it go and hold as long as you can without leaning back.  You can make it harder with a tall box like Mike Boyle does in the video below.

To get a more dynamic, explosive action from your hip flexor try these.

1) Lunge back, push off your front leg and drive the back leg forward and up into your chest (also an amazing exercise to put into a circuit).

2) Do a high knees run from one end of the room to the other, keeping your back upright (it’s so hard if you have weak/tight hip flexors).

3) DO SIT UPS.  (With a bent knee sit up, the iliopsoas is going to be the prime mover of hip flexion).

You should also stretch your hip flexors, but stretching alone is not going to fix the problem.  You’ll just a have a weak, slightly less tight hip flexor (and still be embarrassed in Core class…)


22 thoughts on “I can’t do a Sit Up

  1. janet

    Those hip flexors are easy. No problem to do. Yes i stick my butt out while standing. I’ve been athletic and overweight most of my life. I do possibly 2 situps, incorrectly…when ever i try. Even when playing varsity sports.. crunches? Ummm my neck moves. My shoulders do not leave the ground. I have great definition under the fat, always have. I even have oblique dimples.. still and even can do leg lifts 30, 40, 50 in a row.

    Yet, a proper sit up? No. A proper crunch? No. I have to put my hands under my butt and help with my arms, then i can do ten…maybe

    1. Rachele Pojednic Post author

      Janet, keep trying! It’s only through repetition that our bodies adapt! If using your hands helps, start there! Sometimes when I train my clients, I give them a weight to hold in their hands to reach forward as they sit up. This helps to counterbalance your upper torso. As they get stronger, the weight gets less and less until they can do the whole thing without help. Good luck!

  2. Chris

    This is the first anatomical explanation that seems to offer some help. I think being very large breasted and a very short torso may contribute to the speed at which I can make progress, but I am going to start a regular routine with these.

    1. Rachele Pojednic Post author

      Haha…we all have our genetic challenges to battle, no doubt. I can relate to the short torso! But, we can all make progress with practice! Good luck!

  3. Jennifer

    Thank you. The anatomical pictures are very helpful and it explains so much. I was born with cerebral palsy and it means that my hip fkexors ARE weak and tight. I stand with a highly arched back, almost exactly like the picture. I cannot do a sit up yet as I cannot anchor my feet to the floor in bent knee position. So I am lying on the floor on my back and just practicing isolating my abs by only using them to shorten the length between my hips and ribs. I am also doing leg lifts (bicycle) and working on stretching out all muscles in my legs and hips because every one is tight/weak. I can certainly feel that I worked my abs this morning! So even if I’m not quite there yet at least I’m getting the right muscles to move!
    Thanks again for a well written article,

  4. Lisa Van

    I could aways do sit ups. I had not done them in years, when I tried today, I literally could not do even one. What have I become? I’m mortified.

    1. Rachele Pojednic Post author

      Lisa, Here’s the best thing about the human body: it is 100% adaptable. So, today you can’t do any situps, but you tried. Next week, you can do 1. Next month, you can do 3. And then it’s onwards and upwards from there! Keep working. No excuses. It WILL come!

    1. Rachele Pojednic Post author

      Hi Adil, Start small and work big. One pushup is better than zero pushups. When one leads to two, and two leads to four, you’re onto something! RP

  5. Devon

    Is it only the hip flexors that are weak? I can do the tests you mentioned without problem other than I kind of lose balance and lean left or right, bit back. What about the lumbar muscles? What do I need to do for them?

  6. Marjorie Hague

    Thank you for the insight, I always thought it was the core, stomach muscles that were responsible. I have strong abdominal muscles and could never understand why I couldn’t do this kind of sit up. Now I will start practicing by strengthening the hip flexors.

  7. Amelia

    I am only 12 and I try and try and try to do sit ups, but I can’t. I never have been able to. I try excercises like the ones above for my hips and I hold the position when I’m as far up as possible (which isn’t very far, usually only my shoulders) which has been suggested by my elementary gym teachers to help students with sit-ups. Doing that has helped other kids my age to be able to do sit-ups very easily, but it hasn’t made a difference at all for me. It can be embarrassing during gym when I’m the only one who can’t do sit-ups and it makes me feel unhealthy, though I’m athletic and not overweight. I practice all the time and put lots of effort into trying to improve my sit-ups, but I never make a difference and I’m very confused. I’ve seen the teachers watching me struggle, but they haven’t given me any tips to improve. Can anyone help me?

    1. Rachele Pojednic Post author

      Hey Amelia! I would LOVE to help! In the article, I say that the only way that I can do a sit up alone is by bringing my hands way up over my head and then throwing them forward (giving myself momentum). This may be a GREAT way for you to actually start getting your body to learn this motion. I find that if you take a small hand weight or medicine ball in your hands, lie down on your back with your arms (and the weight) extended over your head, and then swing the weight/ball forward, it is much easier to sit up. Here is a great video by Reebok that demonstrates what I mean: https://www.youtube.com/watch?v=DSjwvV6c1Bs In this video, he is doing more of a crunch, but you can eventually take it all the way up to sitting up tall, bringing the weight forward of your feet. It can also help, when you are first starting out to have someone/something holding down your feet. Good luck and let me know how it goes! RP

  8. Melynda


  9. Joelene

    Hi Rachele , Im in my 20’s and have been aiming to join the army for 3 years now . I aint got no problem with running or any other exercise acxept sit ups . I tried alot also visited proffesors and discovered that I got scoliosis . Planning to start pilates very soon maybe it will help. When I lay on the floor only my shoulder touch the floor and my very lower back. Ther is like an ark that leaves space between my middle back and the floor . Is there something that can help me out with my problem please ? much appreciated

  10. Donna Johnson

    I have an arch in my lower back too and cannot complete a sit up or a roll-up in pilates (I was the only person in my pilates class that couldn’t do one). However, I realised that I could do either when I laid on a soft surface like a bed. After experimenting further I found if I put a small cushion or rolled up towel in the small of my back I can do a sit-up or roll-up easily.

    1. Rachele Pojednic Post author

      This is an awesome tip, Donna! Thank you so much. Everyone’s body is SO different and figuring out how to work with your own body – with all its strengths and challenges- is KEY!

  11. erza

    Hello I want to ask if one has a comparatively flat lower spine by that I mean when I bend down with knees straight only my upper back curves and the lower back becomes horizontal as a result I can’t touch my toes with my hands properly, so I feel maybe it’s the anatomy of my spine that prevents me from doing a crunch or sit up. my aunt’s who have similar straight back can’t do sit ups/crunches as well. I am healthy not over weight don’t have any medical spinal problems. I am just curious about this fact that has come into my notice. And Can you suggest any other core exercises which are equally effective as crunches/sit ups.

    1. Rachele Pojednic Post author

      This is a total problem that I have too! Part of my problem is super tight low back muscles (a combination of genetics, posture habits, and cycling). Both stretching those muscles and choosing alternative core strengthening exercises is key! One that I LOVE is a hanging crunch. You can do this with a pullup bar or hanging arm straps. You basically let yourself hang with arms long, and then bring your knees up to your chest. You can advance this exercise by adding some twisting and eventually keeping your legs straight. Good luck!

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